Five years of renewed funding is requested for the National Magnetic Resonance Facility at Madison (NMRFAM) which is located in the University of Wisconsin Biochemistry Department. This shared instrumentation facility houses four modern superconducting NMR spectrometers: one 51 mm 14.09 tesla (600 MHz proton frequency), two 51 mm 11.74 tesla (500 MHz), and one 89 mm 9.4 tesla (400 MHz). Off-line data stations each with an array processor are used to analyze and plot NMR results. The first-year equipment budget request includes funds to (i) complete payment for one of the installed 11.74 tesla spectrometers and one of the data stations, (ii) purchase a computer to be used for processing multidimensional NMR data sets and for calculating and displaying structural and dynamic results, and (iii) purchase test instrumentation needed for core and collaborative research and service activities. The core research of the facility focuses on structure-function investigations of proteins, isotopic labeling of biomolecules for multinuclear NMR analysis, software development for processing and display of multidimensional NMR data, development and distribution of a protein NMR database, and multinuclear magnetic resonance studies of living cells and intact tissues. NMRFAM will continue to endeavor to provide the latest equipment and techniques in high-resolution, multinuclear magnetic resonance experimentation for collaborative and service projects covering several biomedical areas: structure and function of proteins, nucleic acids, and natural products; active sites and mechanisms of enzymes; modes of action of drugs; and physiological levels of metabolites in living cells and organisms. NMRFAM staff train users of the facility and conduct informal practical courses and workshops on NMR theory and applications. Dissemination of research results is through publications and presentations at meetings and by distribution of the NMR database and software packages. The progress and administration of the facility is reviewed regularly by an Advisory Committee of experts in the field of biological NMR, who also evaluate the research proposals of long- term users. A Local Steering Committee consisting of representatives from major user departments on the Madison campus, deals with local concerns and makes an annual report to the Advisory Committee.